The present invention is directed to a yarn clamp which is particularly suitable for use with a piece of textile equipment known as a Unifil Winder produced by the Leesona Corporation of Warwick, Rhode Island.
During the process of manufacturing fabric using a Unifil Winder, yarn is dispensed from a bobbin by means of a shuttle in order to provide the fill for the fabric. As the yarn supply on the bobbin becomes depleted, it is necessary to replace the bobbin with a new one. The need for such replacement is detected by a fill feeler associated with the loom. The feeler actuates a transfer mechanism to effect the bobbin transfer.
Prior to the bobbin transfer operation, the yarn tail of the replacement bobbin is held by the holding and tensioning drum. Thus, proper tension exists on the yarn between the holding drum and the replacement bobbin that is properly positioned for transfer in the Unifil Winder.
At the time of transfer, it is essential that the yarn tail of the replacement bobbin be securely held. If proper clamping does not occur, this tail will be pulled away from the holding drum, causing either defective fabric to be produced or the loom to stop due to detecting of the absence of a fill thread. However, with the tail firmly clamped, the integrity of the fill is maintained throughout the transfer operation.
Conventionally, clamps used with a Unifil Winder are of the general type disclosed in U.S. Pat. No. 3,411,550 to Jenkins and U.S. Pat. No. 3,452,784 to Sides. Such clamps are formed by complex mechanical linkages which are expensive, and they suffer additional shortcomings such as short life, difficulty in maintaining proper adjustment, lack of control of clamping tension, and the like.
Another prior art yarn clamp is disclosed in U.S. Pat. No. 3,797,532 to Haltmeier. While this clamp is structurally more similar to the present invention than are the clamps represented by U.S. Pat. Nos. 3,411,550 and 3,452,784, it also has disadvantages of the type just described.
The yarn clamp according to the present invention structurally is considerably simpler and less expensive than conventional clamps. Additionally, it is not as subject to wear, has adjustable clamp tension, will hold yarn securely and requires less adjustment than conventional clamps.